Psalm 119:18-20

Open my eyes (to spiritual truth) so that I may behold wonderful things from Your law. I am a stranger on the earth; do not hide Your commandments from me. My soul is crushed with longing for Your ordinances at all times. 

When God reveals spiritual truths to our hearts, we grow in our spiritual walk. The more we learn about God and His desire for us to receive His best, the more we want to learn. God is all that is good, and when we see that He wants all that is good for us, we long for an even closer relationship.